Prior U.S. Pat. No. 4,277,998 discloses an apparatus for cutting wooden truss components at various required angles of cut with precision and on a high volume basis. In the patented apparatus, pieces of lumber are conveyed past a plurality of relatively stationary power driven rotating circular saw blades which are preadjusted to provide the desired cutting angles and prepositioned to establish the required lengths of cut components. In the apparatus, the saw blades are arranged in opposing pairs or groups on two support systems, one of which is fixed and the other of which is movable toward and away from the fixed system. Means is provided on each support system to adjust the saw blades thereon angularly. The established distance between the two support systems determines the length of components being cut.
A pair of lumber conveyors are mounted on each saw blade support system to move the lumber through the rotating saw blades at a uniform rate with the longitudinal axis of the lumber perpendicular to its path of travel past the saw blades. To maintain this relationship, the conveyors on the two support systems are driven synchronously.
In order that the length of the cut lumber not change when the angle of the saw blades is changed, the outer or forward face of each saw blade must rotate around a pre-established precision pivot axis.
In the practical use of the prior patented machine, it has been discovered that it is virtually impossible to position the opposing groups of saw blades on the two support systems and maintain their positioning with the outer faces of the blades precisely located on the described pivot axes. The inevitable build up of machine tolerances in the apparatus, which is a relatively large apparatus, renders it almost impossible to adjust the saw blades with sufficient precision to achieve the objectives stated in the prior patent with conventional adjusting means built into the apparatus.
Accordingly, it is the prime object of this invention to provide a precision adjustment system for the apparatus disclosed in the above-mentioned patent which will enable the positioning of the saw blades on the two support systems with their outer faces exactly on the predetermined axes around which the saw blades must pivot to various angle cutting positions without changing the lengths of truss components being cut by the apparatus.
More particularly, the present invention provides a complete series of adjustments of the saw blades on each support system of the apparatus whereby the blades of each support system can be bodily raised and lowered and bodily adjusted in a horizontal plane in all directions. Furthermore, in accordance with this invention, the individual saw blades and their drive motor mounts are adjustable on the pantograph linkage which carries them, and the gear sectors around which the individual saw blades and the associated pantograph linkages travel are adjustable bodily in multiple directions on the primary support system.
In essence, the present invention provides a complete substantially universal adjusting system for the saw blades of the apparatus assuring that each blade can be precisely located on the required pivot axis and will remain on such axis in all angularly adjusted positions of the blade. The disclosed adjusting system is critical and necessary for a completely successful employment of the apparatus in U.S. Pat. No. 4,277,998 to achieve the maximum benefits thereof in the cutting of truss lumber components.
While the present invention is disclosed in terms of a primary support system on which a single pair of saw blades are mounted, it should be understood that the invention is not limited to this arrangement and additional pairs of blades can be provided on additional primary supports in the apparatus and adjusted with precision by means of the disclosed universal adjusting means. Furthermore, the invention is not limited to adjusting saw blades and may be employed in connection with any rotating cutting tool required to cut any type of material.